Rotary pump



p 4, 1934- o. SIEMEN r-:r AL 1,972,410

ROTARY PUMP Filed May 17-, 19

"invenor;

0R0 Siemen Aunt-neg Patented Sept. 4, 1934 UNITED STATES ROTARY PUMP I Otto Siemen and Johannes Hinsch, Itaehoe, Schleswig Holstein, Germany Application May 17, 1932, Serial No. 611,856

In Germany February 1, 1932 2 Claims.

The present invention relates to rotary pumps of the type in which a. vaned impeller wheel rotates in a surrounding and closely fitting casing. Rotary pumps are characterized by the fact that inoperation no valve mechanisms are necessary in order to procure a pumping, action. Accordingly, to provide unobstructed passage of the liquid being pumped, no valves are provided and, as a result, the liquid being pumped tends to drain back through the said pump when the latter is stopped, thereby removing a large part of the liquid from within the pump casing. Furthermore, when the pump is out of use for a long period of time, the portions of the impeller which extend above the water level of the pump may become oxidized, so that it is impossible to start the pump without damage to the impeller or to the casing in which the impeller is mounted. It is accord.- ingly the principal object of the present invention to provide! for completely submerging the pump inthe liquid being pumped during the time that the pump is inoperative.

Other and further objects and advantages will appear from the following detailed description taken in connection with the accompanying drawing, in which:--

Fig. 1 is a vertical section through a pump embodying the invention.

Fig. 2 is anelevation of a different pump construction showing a modification, parts being broken away.

Fig. 3 is a fragmentary section of a portion of a pump showing a further modification.

Like reference characters refer to like parts in the different figures.

Referring particularly to Fig. 1, the pump comprises a casing 1 having vertically spaced horizontal pumping chambers 2, 3 in which varied impellers 4, 5 are rotatably mounted. Said impellers 4, 5 are secured to a drive shaft 6, the latter being journalled in the casing 1 and being driven in any suitable manner. The pumping action is procured by rotation of the impellers 4, 5 within the chambers 2, 3 in which they are eccentrically mounted, as shown. The rotation of the impellers procures escape of the liquid in the chamber from the pockets between the vanes by centrifugal force, thereby forming a vacuum in said pockets to draw the liquid being pumped into said pockets and subsequent return of the liquid into said pockets thereby creating a, pressure on the liquid being pumped to force it out of the pump chamber, as in the usual rotary or centrifugal pump construction.

In the arrangement shown, the pumpoperates as a multi-stage pump with the lower impeller 4 drawing the liquid being pumped through an inlet opening 7 in the casing 1 into the chamber 2, said liquid being exhausted through a port 8 'into the upper chamber 3 from which it is delivered by the impeller 5 through an outlet port 9 into an annular chamber 10. The latter is formed on the under side of a cover 11 which provides an air-tight closure for a tank 12 within which the pump is mounted, and liquid in the chamber 10 exhausts through a port 13 in said cover into the outlet pipe 14. The pump casing is secured to the cover 11 beneath the chamber 10 to form a closure for the bottom side thereof. The inlet port 7 to the pump is located within the tank 12 and a pipe 15 extends from said port substantially to the top of said tank. Liquid enters the tank 12 through an inlet port 16 provided in the cover 11, said port being connected by a pipe 17 to any suitable source of liquid, indicated diagrammatically at l8.

With the pump in operation, the liquid being pumped is drawn from the supply 18 through the pipe 1'7 into the tank 12 which is sufliciently large to permit any dirt or other impurities in the liquid to settle therefrom before said liquid is drawn into the pump through the pipe .15, the latter being arranged, as above stated,- to draw the liquid being pumped from adjacent the top of the tank, thus maintaining said tank substantially full of liquid with the normal level of said liquid material above the pump. The liquid being pumped passes through said pump and is discharged into the chamber 10 from which it exhausts through the outlet pipe 14.

When the impellers 4, 5 are brought-to rest, the liquid in the supply pipe 17, in the absence of any valves in the pump returns by gravity to the supply 18, thereby drawing air in through the outlet pipe 14 and through the pump, and removing substantially all the liquid in the pump.

The air entering the pump discharges through the pipe 15 into the tank 12, and thence into the pipe 17, leaving the tank 12 substantially full of liquid.

When the liquid has siphoned out of the pipe 17 into the supply 18, the above describedv pump structure is such that the liquid in the tank 12- cannot return into the pump chambers 2, 3 since the liquid in said tank is held in equilibrium by the liquid in the lowerend of the pipe 17. It will be noted that the liquid in the tank 12 surrounds the pump at a substantially higher level than the impellers of said pump, and liquid in said tank can enter the pump chambers 2, 3 by the admission of air to the upper portion of the tank 12. To this end a bleed port 19 is provided'in the pump casing, or in the cover 11, said port providing a connection from the chamber 10 or the bers through small ports 20 or 21 formed in the sides of the pipe 15, below the normal liquid level of the tank. The port 19 allows the pressure in the chamber 10 and the tank 12 to be equalized so that the liquid within the pump and the liquid in the tank surrounding the pump reach the same level and the pump is thus entirely submerged in liquid when said pump is not in operation. The port 19, during the operation of the pump, is below the water level in the chamber 10 and the passage-of air through said port is accordingly impossible during the operation of the pump. When the pump is brought to rest'and the liquid in the supply pipe 1'7 returns to the source 18, the liquid in the chamber 10 is replaced by air through the pipe 14 to bring the liquid level below the port 19 and allow air to enter the tank 12 through said port. The bleed port 19 and the ports 20 and 21 are of relatively small size compared to the inlet and outlet ports of the pump, and do not interfere appreciably with the pumping action of said pump, the small amount of liquid passing through the port 19 during the operation of the pump, as well as the small amount of liquid entering the pipe 15 through the ports 20 and 21, being negligible as compared to the total amount of liquid pumped through the tank. Referring now to Fig. 2, which shows a modification of the device, the pump casing 1a is mounted on the under side of the tank 12a and, in operation, the pump in said casing draws liquid from adjacent the top of said tank through the pipe 15a extending from the inlet port of said pump into the pump, as a result of the equalizing of the pressures in the chamber and tank, through a port 201;. extending through the side of the pipe 15a, below the liquid level of the tank.

In the modification of Fig. 3, the bleed port 19 or 19a is replaced by channels 22 or 23 which extend through the pump casing and provide a connection between annular chambers 24 surjrounding the shaft 6 of the pump and the tank 12. Inthis construction, air from the outlet pipe 14 enters through the upper pump chamber 3 into the lower of the annular chambers 24. The annular chambers 24 are interconnected by a bore 25 in the pump casing through which the drive shaft 6 extends, said bore being somewhatlarger in diameter than said shaft to permit air to pass between said chambers 24. In this manner, air from the outlet port may enter through the pump chamber (corresponding to the chamber 3, Fig. 1) into either of the chambers 24 and pass through the channel 22 or 23 into the tank 12 to equalize the pressures in said tank and in the outlet pipe 14 to permit the liquid in the tank to flow by gravity into the pump to submerge the imp'elleraof said pump during the periods when the pump is not in operation. As'soon as the pump starts, liquid enters the lower chamber 24 and preventsthe exhaust of air through either the channel 23 or 22, so that the restricted connection between the outlet port of the pump and the chamber 12 is effectively closed during the operation of the pump.

When the pump is started, a certain amount of air enters the pump through the pipe 15 from the upper portion of the chamber 12 and the'liquid in the pump is discharged through the exhaust port 9 of said pump. In order to main- .tain a sufficient amount of liquid in the pump so that the latter will operate and continue to pump air and water from-the upper portion of the chamber, the port 21 admits continually a small amount of liquid into the pipe 15 which enters the pump and replenishes the supply of pumping fluid during the time that the pump is pumping some air from the upper portion of the chamber. By the location of the inlet to the pump adjacent the top of the chamber 12 and spaced horizontally from the inlet to the chamber, it is possible for the chamber to act .as a

settling tank so that no foreign matter entering the tank will enter the pump;

From the above, it will be noted that the present construction provides for maintaining the impellers of the pump submerged in the liquid being pumped while said pump is not in operation, by filling the casing of the pump full of liquid from the tank 12 when the pump is stopped. Since the pump is entirely submerged, there is'always liquid within the pump chamber so that it is not necessary to prime the pump when starting it.

We claim:

1. In a pumping system, the combination with a tank having a pump casing therein below the normal level of liquid in said tank, a pump impeller mounted in a chamber in said casing, and a shaft for said pump extending upwardly therefrom and journalled in a portion of said tank, of a suction pipe connected to the inlet of the pumpopening to the interior of the tank adjacent the top thereof, said tank having an inlet adjacent the top thereof and out of the line of direct communication withthe suction pump opening, said tank also having a small chamber therein above the pump and surrounding the I pump shaft and communicating with the chamber provided for the pump impeller, a restricted connection between the small chamber and the interior of the tank and a restricted connection between the interior of the tank and the pump chamber below the normal liquid level of the tank and substantially above the bottom thereof.

2. In a pumping system, the combination with a tank having a pump casing therein below the normal level of liquid in said tank, a pump impeller mounted in a chamber in said casing, and a shaft for said pump extending upwardly therefrom, of a suction line connected to the inlet of the pump and opening to the interior of the tank adjacent the top thereof, said tank having an inlet adjacent the top thereof and out of the line of direct communication with the opening to the suction line, said tank also having a small chamber therein above the pump and communicating with the chamber provided for the pump impeller, a restricted connection between the small chamber and the interior of the tank, and a restricted connection between the interior of the tank and the pump chamber below the normal liquid level of the tank and substantially above the bottom thereof.

OTTO SIEMEN, JOHANNES HINSCH. 

